Kicking off this week’s must-have apps list is a new to-do app called Checkmark, which is being labeled the reminders app Apple should have made. There’s also a great new video sharing service called Vyclone, a unique clock app, and more.

Checkmark is the reminders app Apple should have made. You’ve probably seen this app around the Internet a lot since its release earlier this week, because it’s fantastic, and everyone’s talking about it. “Checkmark is the fastest way to remind yourself of all the things you have to do in your busy life,” its App Store description reads.

Checkmark sports a great, simple user interface, which makes it quick and easy to create date, time, or location-based reminders. You can tell it to remind you to pay a bill at the end of the month, or to hand in that report tomorrow — just like any other to-do app.

But Checkmark will also remind you of things when you arrive at a certain location, or when you leave a certain location. So you can have it alert you to buy milk when you leave the office, or to pick up your laundry as you’re walking past the laundromat on the way home.

Checkmark is just $0.99 to celebrate its launch, so grab it while it’s cheap. You won’t regret it.

Vyclone is a really clever app that helps you share video with your friends. But it’s not just another place to post videos of your cat for the world to see. Instead, you use Vyclone with your friends while you’re all filming something great — like your favorite band at a festival — and it automatically synchronizes and edits everyone’s clips to create one movie that features all of the angles you’ve shot together.

It then provides you with the raw footage, so you can also make manual edits as you please. Only when your masterpiece is finished do you share it online. “It’s filming genius,” Vyclone promises.

If you have your iPhone or iPad docked on your desk while you’re working, give it a purpose with Chameleon Clock, a “big, bold, beautiful clock.” Chameleon is really simple. There are no fancy animations or lengthy weather reports you’re not interested in. It just shows the time and date in big, bold numbers.

You can either choose one of the built-in sample wallpapers for your clock’s background, or you can make it transparent by using your device’s rear-facing camera to provide a live video feed of everything that’s happening in the background.

If you have an Xbox 360 and an iOS device, you should be using My Xbox LIVE. It allows you to track and compare your achievements, see who’s online and send and receive messages, customize your Xbox LIVE avatar, and more.

But its best feature comes in the latest update. My Xbox LIVE now allows you to use your iOS device as a remote control for your console. You can use it to navigate your way around the menus, control media playback, and to “find fresh entertainment” in the new Discover section.

Setup is as easy as ensuring both your Xbox and your iPad are logged in to the same Xbox LIVE ID, and that “Xbox Companion” is enabled on your console. You don’t even need to be connected to the same Wi-Fi network, though the app does advise you to do this for a speedy connection.

What’s Your Favorite?

So that concludes our list of this week’s must-have iOS apps. If you’ve picked up something that you think we should have included, be sure to let us know about it in the comments.